An anesthesia system anesthetizing a patient includes: an anesthetic vaporizer vaporizing a volatile anesthetic and regulating the concentration of the vaporized anesthetic gas; and an anesthetic tank supplying the anesthetic vaporizer with an anesthetic. The anesthetic tank is arranged inside of the anesthetic vaporizer, or alternatively, is separated from the anesthetic vaporizer and connected via piping to the anesthetic vaporizer. The thus-configured anesthetic tank includes an anesthetic injection portion for injecting a volatile anesthetic from an anesthetic container having a bottle shape. The anesthetic injection portion is provided with a substantially cylindrical insertion mouth communicating with the anesthetic tank. On the other hand, the anesthetic container is provided with a mouth portion, and on the periphery of the mouth portion, a mouth thread is formed and used for setting an injection adapter. The injection adapter is provided with a substantially cylindrical insertion portion inserted into the insertion mouth of the anesthetic injection portion. The injection adapter is inserted into the anesthetic injection portion, so that the volatile anesthetic can be injected from the anesthetic container through the injection adapter and the anesthetic injection portion into the anesthetic tank.
There are several types of anesthetics such as sevoflurane, isoflurane, enflurane and halothane, and the individual types of anesthetics differ in the properties such as the boiling point, the saturated vapor pressure and the MAC (minimum alveolar concentration). In order to realize the concentration of a volatile anesthetic with precision, an exclusive anesthetic vaporizer is needed for each type of volatile anesthetic (e.g., refer to Non-Patent Document 1). Hence, a medical facility manages to prevent a specified type of volatile anesthetic from being injected into an anesthetic tank different from the exclusive one. For the purpose of ensuring this management, systems for preventing an erroneous anesthetic injection were invented which determine an injection adapter and an anesthetic vaporizer for every type of volatile anesthetic and thereby prevent the injection of a volatile anesthetic unsuitable for an anesthetic vaporizer (e.g., refer to Patent Documents 1 to 4).
Patent Document 1 provides a system for preventing an erroneous anesthetic injection which includes: a set of keys formed in an insertion portion of an injection adapter thereof, the set of keys indicating the type of a volatile anesthetic by the widths of the keys and the arrangement intervals between the keys; and a set of key groove formed in an insertion mouth of an anesthetic injection portion thereof, the set of key groove having the widths and the arrangement intervals fit for the set of keys of the injection adapter. Therefore, if the keys of the insertion portion engage with the key groove of the insertion mouth, then the insertion portion is inserted into the insertion mouth, thereby preventing an erroneous injection of the volatile anesthetic.
Patent Document 2 provides a system for preventing an erroneous anesthetic injection which includes: a polygonal key formed in the peripheral surface of an insertion portion of an injection adapter thereof, the key indicating the type of a volatile anesthetic by the number of the angles, and a set of key groove formed in the front end of the insertion portion, the set of key groove being shaped like the teeth of a comb and the key groove being equal in number to the angles of the polygonal key; and a polygonal keyhole formed in an insertion mouth of an anesthetic injection portion thereof, the polygonal keyhole being fit for the polygonal key of the injection adapter, and a set of keys formed in the insertion mouth, the set of keys being shaped like the teeth of a comb and being fit for the set of key groove shaped like the teeth of a comb. Therefore, if the polygonal key and the comb-teeth key groove of the insertion portion engage with the polygonal keyhole and the comb-teeth keys of the insertion mouth respectively, then the insertion portion is inserted into the insertion mouth, thereby preventing an erroneous injection of the volatile anesthetic.
Patent Document 3 provides a system for preventing an erroneous anesthetic injection which includes: a cylindrical member formed in an insertion portion of an injection adapter thereof, the cylindrical member being rotatable around the center axis of the insertion portion and being formed in the peripheral surface thereof with a set of keys indicating the type of a volatile anesthetic by the number of the keys and the arrangement intervals between the keys; and a set of key groove formed in an insertion mouth of an anesthetic injection portion thereof, the set of key groove being fit for the set of keys of the injection adapter. Therefore, if the keys of the insertion portion engage with the key groove of the insertion mouth, then the insertion portion is inserted into the insertion mouth, thereby preventing an erroneous injection of the volatile anesthetic.
Patent Document 4 provides a system for preventing an erroneous anesthetic injection which includes an injection adapter and an anesthetic injection portion the configurations of which are similar to those of Patent Document 2. The injection adapter has an insertion portion formed with a polygonal key and a set of key groove shaped like the teeth of a comb, the insertion portion being rotatable around the insertion axis thereof with respect to the injection adapter. The anesthetic injection portion has an insertion mouth formed with a polygonal keyhole and a set of keys shaped like the teeth of a comb, the insertion mouth being arranged inside of a cylindrical stub (filler connection stub). The stub is rotatable around the insertion axis thereof with respect to the anesthetic injection portion. In the connection region between the injection adapter and the anesthetic injection portion, an insertion assistant portion is provided, the insertion assistant portion being used for positioning (centering) the polygonal key and the polygonal keyhole so that the former is fitted into the latter.
In the systems for preventing an erroneous anesthetic injection according to Patent Documents 1 and 2, a person needs to insert the injection adapter into the anesthetic injection portion while checking the positions of the keys and the key groove through visual or touching inspection. This would complicate the injection work. Besides, when the keys of the injection adapter engage with the key groove of the anesthetic injection portion, the anesthetic container may be rotated to loosen the attachment of the injection adapter, thereby causing the anesthetic container to leak the volatile anesthetic.
In the system for preventing an erroneous anesthetic injection according to Patent Document 3, the cylindrical member of the injection adapter is rotated and thereby leads the keys to engage with the key groove. Therefore, the attachment of the injection adapter cannot be loosened, thereby hindering the anesthetic container from leaking the volatile anesthetic. However, the small cylindrical member located at the front end of the injection adapter needs rotating so that the keys and the key groove engage each other. Accordingly, it is impossible to simplify the injection work.
In contrast, in the system for preventing an erroneous anesthetic injection according to Patent Document 4, upon inserting the insertion portion of the injection adapter into the insertion mouth of the anesthetic injection portion, the insertion assistant portion rotates the insertion mouth and the stub so that the polygonal key of the former is fitted into the polygonal keyhole of the latter. Therefore, the key can be easily fitted into the keyhole, thereby avoiding loosening the attachment of the injection adapter and hence preventing the anesthetic container from leaking the volatile anesthetic.